The utilization of volatile substances for air fresheners, fragrances, and other air-treating dispensing applications is relatively wide-spread and provided in a number of structural arrangements. As described in U.S. Pat. No. 4,157,787, which is issued to B. Schwartz, a number of air-freshening type dispensing products comprise a quantity of air-treating material, which, when exposed to the atmosphere, is to release its active substances in a predetermined, controlled manner in the form of vapor. Consequently, during the period of time in which these products are not in use (e.g. during shipping, storage, etc.), it is desirable to prevent the vaporization of the active substances to prevent premature release of the fragrance or other air-treating active substances. Conventionally, the dispenser itself is sealed with a cover layer of nonporous material to prevent vaporization of the active substances. The Schwartz air freshener dispenser is described as including a porous layer which covers the opening of the dispenser and underlies a removable, non-porous seal or cover layer. Removal of the non-porous layer enables permeation and vaporization to begin.
U.S. Pat. No. 4,130,245, which issued to J. Bryson, discloses a liquid dispensing package designed to provide a more uniform dispensing rate by maintaining maximum surface contact between the volatile substance held therewithin and the interior surfaces of the package. The Bryson device incorporates an outer porous layer superposed over a heat-sealable plastic layer to assist in heat-sealing manufacturing procedures. Bryson does not specifically provide any particular packaging system for its dispensing device. Another vapor-type dispensing product is shown in U.S. Pat. No. 4,356,969, which issued to A. Obermayer et al. While this dispensing device contemplates utilization of a macroporous overlay sheath material to control the rate of evaporation of its volatile substances, additional packaging not included in this patent would be necessary to enclose this dispenser for transportation and storage.
Another device for treating ambient air is set forth in U.S. Pat. No. 4,634,614, which issued to G. Holzner. The Holzner device includes an active substance containing chamber, a permeable wall covering that chamber, a thin paper layer attached to the outer surface of the permeable wall, and a polymeric material having a sheet of protective impermeable material such as metal foil attached to the outer surface of the paper. The impermeable material prevents migration of active substances and vaporization, and the paper layer enables detachment of the polymeric and impermeable material from the permeable wall when dispensing is desired. Particularly, the paper layer tears away from the permeable wall, allowing permeation and vaporization to begin. A somewhat similar device is shown in U.S. Pat. No. 4,161,283, which issued to S. Hyman. The Hyman device includes a pouch or envelope defined by an outer wall including a first barrier layer which is impermeable to diffusion, and an inner polymer diffusion layer. When use of the device is desired, the outer barrier layer is removed, and diffusion and vaporization is thereby enabled through the polymeric diffusion layer.
A somewhat related device is shown in U.S. Pat. No. 4,055,672, which issued to A. Hirsch et al. In this reference, a pre-formed tray has heat-sealable flanges to which a composite lid is sealingly attached. The lid includes an inner layer of highly gas permeable material, an outer layer which is substantially gas impermeable, and a central adhesive layer which has a strength lower than the cohesive strength of the inner layer. When permeation from the package is desired, the outer layer is peeled away from the inner layer and along with the adhesive layer for removal from the package.
The Weyenberg et al. package shown in U.S. Pat. No. 4,145,001 similarly includes a multi-layer laminate having an outer layer impermeable to the contained substance and its vapors, with the outer layer being adhered to an inner permeable layer. These inner and outer layers are connected by a release layer which enables selective removal of the outer impermeable layer to commence permeation and vaporization of the active substances. Application of a package as described in the Weinberg et al. patent is shown in the later U.S. Pat. No. 4,849,606, which issued to E. Martens et al. In the Martens reference, a container for active substances is provided with a peripheral flange to which the multi-layer laminate as described in Weinberg et al. is sealed. The resulting tamper-resistant container is described as appropriate for use with air freshening substances and the like in conjunction with an electrically heated vapor dispensing apparatus. When air freshening is desired, the impermeable layer of the container is removed to expose the permeable layer for dispensing procedures.
While it is clear that there are a number of prior dispensing and packaging structures which incorporate the use of specially designed plural laminates which enable selective removal of an impermeable protective layer from a permeable membrane or cover of a dispensing cartridge, these relatively complex laminate structures are not always feasibly available or desired for all applications. On the other hand, packages for containing cartridges of volatile substances having a permeable surface must be able to contain such substances so as to prevent the premature consumption of the volatile or active substance, and to prevent undesirable contact by the user with various oils and other substances which can move through the permeable surface. A simple yet reliable packaging system for containing volatile cartridges with a permeable membrane was needed and has heretofore been unavailable in the industry.